The lock cylinder has a bad habit of getting gunked-up and sticking. If it's had much use, you're probably money ahead to replace it while you've got the column dismantled. Just about any good parts store will have a replacement cylinder in stock, with keys.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!